P04298 · MCEL_VACCW
- ProteinmRNA-capping enzyme catalytic subunit
- GeneOPG113
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids844 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Catalytic subunit of the mRNA capping enzyme which catalyzes three enzymatic reactions: the 5' triphosphate end of the pre-mRNA is hydrolyzed to a diphosphate by RNA 5' triphosphatase; the diphosphate RNA end is capped with GMP by RNA guanylyltransferase and the GpppN cap is methylated by RNA (guanine-N7) methyltransferase. Heterodimeric mRNA capping enzyme catalyzes the linkage of a N7-methyl-guanosine moiety to the first transcribed nucleotide (cap 0 structure), whereas the methyltransferase OPG102 is responsible for a second methylation at the 2'-O position of the ribose (cap 1 structure). Also involved in early viral gene transcription termination and intermediate viral gene transcription initiation. Early gene transcription termination requires the termination factor VTF, the DNA-dependent ATPase NPH-I/OPG123 and the RAP94/OPG109 subunit of the viral RNA polymerase, as well as the presence of a specific termination motif. Binds, together with RAP94/OPG109, to the termination motif 5'-UUUUUNU-3' in the nascent early mRNA.
Catalytic activity
- a 5'-end triphospho-ribonucleoside in mRNA + H2O = a 5'-end diphospho-ribonucleoside in mRNA + phosphate + H+This reaction proceeds in the forward direction.
Cofactor
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
23 μM | GpppA |
A-570 and A-763 mutants have 3-fold and 10-fold higher Km values for GpppA.
Features
Showing features for binding site, site, active site.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Binding site | 37 | Mg2+ (UniProtKB | ChEBI); catalytic; for RNA triphosphatase activity | |||
Binding site | 39 | Mg2+ (UniProtKB | ChEBI); catalytic; for RNA triphosphatase activity | |||
Site | 77 | Essential for RNA triphosphatase activity | |||
Site | 107 | Essential for RNA triphosphatase activity | |||
Site | 126 | Essential for RNA triphosphatase activity | |||
Site | 159 | Essential for RNA triphosphatase activity | |||
Site | 161 | Essential for RNA triphosphatase activity | |||
Binding site | 192 | Mg2+ (UniProtKB | ChEBI); catalytic; for RNA triphosphatase activity | |||
Binding site | 194 | Mg2+ (UniProtKB | ChEBI); catalytic; for RNA triphosphatase activity | |||
Active site | 260 | N6-GMP-lysine intermediate | |||
Binding site | 549-550 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | |||
Binding site | 569-570 | mRNA cap of mRNA (UniProtKB | ChEBI) | |||
Binding site | 573 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | |||
Binding site | 598 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | |||
Site | 607 | mRNA cap binding | |||
Binding site | 620 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | |||
Site | 632 | mRNA cap binding | |||
Binding site | 678-680 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | |||
Site | 682 | mRNA cap binding | |||
Site | 763 | mRNA cap binding | |||
Site | 836 | mRNA cap binding | |||
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | virion component | |
Molecular Function | GTP binding | |
Molecular Function | inorganic triphosphate phosphatase activity | |
Molecular Function | metal ion binding | |
Molecular Function | mRNA 5'-cap (guanine-N7-)-methyltransferase activity | |
Molecular Function | mRNA 5'-triphosphate monophosphatase activity | |
Molecular Function | mRNA guanylyltransferase activity | |
Molecular Function | polynucleotide 5'-phosphatase activity | |
Molecular Function | RNA binding | |
Biological Process | DNA-templated transcription termination |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended namemRNA-capping enzyme catalytic subunit
- Alternative names
Including 3 domains:
- Recommended namePolynucleotide 5'-triphosphatase
- EC number
- Alternative names
- Recommended namemRNA guanylyltransferase
- EC number
- Alternative names
- Recommended namemRNA (guanine-N(7))-methyltransferase
- EC number
- Alternative names
Gene names
Organism names
- Taxonomic lineageViruses > Varidnaviria > Bamfordvirae > Nucleocytoviricota > Pokkesviricetes > Chitovirales > Poxviridae > Chordopoxvirinae > Orthopoxvirus > Vaccinia virus
- Virus hosts
Accessions
- Primary accessionP04298
- Secondary accessions
Proteomes
Subcellular Location
UniProt Annotation
GO Annotation
Note: All the enzymes and other proteins required to synthesize early mRNAs are packaged within the virion core along with the DNA genome.
Keywords
- Cellular component
Phenotypes & Variants
Features
Showing features for mutagenesis, natural variant.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Mutagenesis | 77-79 | Almost complete loss of RNA triphosphatase activity, 70% loss of guanylyltransferase activity. | |||
Mutagenesis | 107 | Complete loss of triphosphatase activity, no effect on guanylyltransferase activity. | |||
Mutagenesis | 126 | Complete loss of triphosphatase activity, no effect on guanylyltransferase activity. | |||
Mutagenesis | 135-136 | 70% loss of RNA triphosphatase activity, 40% loss of guanylyltransferase activity. | |||
Mutagenesis | 159 | Complete loss of triphosphatase activity, no effect on guanylyltransferase activity. | |||
Mutagenesis | 161 | Complete loss of triphosphatase activity, no effect on guanylyltransferase activity. | |||
Mutagenesis | 192-194 | Complete loss of RNA triphosphatase activity, 50% loss of guanylyltransferase activity. | |||
Mutagenesis | 260 | Complete loss of guanylyltransferase activity, no effect on RNA triphosphatase activity. | |||
Mutagenesis | 524-526 | 50% loss of RNA triphosphatase activity and 40% loss of guanylyltransferase activity. | |||
Mutagenesis | 570 | Retains substantial methyltransferase activity in vitro; lethal in vivo. | |||
Mutagenesis | 573 | Complete loss of methyltransferase activity; lethal in vivo. | |||
Mutagenesis | 607 | Retains substantial methyltransferase activity in vitro; lethal in vivo. | |||
Mutagenesis | 608 | Almost complete loss of methyltransferase activity; lethal in vivo. | |||
Mutagenesis | 676 | Complete loss of methyltransferase activity; lethal in vivo. | |||
Mutagenesis | 679 | Almost complete loss of methyltransferase activity; lethal in vivo. | |||
Mutagenesis | 682 | Complete loss of methyltransferase activity; lethal in vivo. | |||
Natural variant | 705 | in strain: mutant Dts36 | |||
Mutagenesis | 763 | Retains substantial methyltransferase activity in vitro; lethal in vivo. | |||
Variants
![](/variants.8e7f84.jpg)
We now provide the "Disease & Variants" viewer in its own tab.
The viewer provides 1 variant from UniProt as well as other sources including ClinVar and dbSNP.
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Chain | PRO_0000210124 | 1-844 | mRNA-capping enzyme catalytic subunit | ||
Interaction
Subunit
Forms a heterodimer with the regulatory subunit OPG124.
Binary interactions
Type | Entry 1 | Entry 2 | Number of experiments | IntAct | |
---|---|---|---|---|---|
BINARY | P04298 | OPG124 P04318 | 3 | EBI-16095746, EBI-16095776 |
Protein-protein interaction databases
Structure
Family & Domains
Features
Showing features for region, domain.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Region | 1-539 | Triphosphatase-guanylyltransferase | |||
Domain | 516-844 | mRNA cap 0 methyltransferase | |||
Domain
The N-terminus contains the triphosphatase and guanylyltransferase domains, whereas the C-terminus contains the methyltransferase domain. The N-terminus is involved in binding to the termination motif 5'-UUUUUNU-3' in the nascent mRNA.
Sequence similarities
In the N-terminal section; belongs to the dsDNA virus mRNA guanylyltransferase family.
In the C-terminal section; belongs to the class I-like SAM-binding methyltransferase superfamily. mRNA cap 0 methyltransferase family.
Family and domain databases
Sequence
- Sequence statusComplete
- Length844
- Mass (Da)96,734
- Last updated1987-03-20 v1
- MD5 Checksum75C8086390B222FC389AEA9468829EE5
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
M15058 EMBL· GenBank· DDBJ | AAA48253.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
AY243312 EMBL· GenBank· DDBJ | AAO89385.1 EMBL· GenBank· DDBJ | Genomic DNA |